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Control Files

FIXLINK (fixlink=filename)

The format of the fixlink file is exactly the same as that of the bblink file. This file is used to tell NorthStar Planner that the links specified in this file should not be deleted during backbone link design.

LINKDIST (linkdist=filename)

This file contains default distances (admin weights) that can be assigned between backbone nodes. If the hopdist design parameter (in the dparam file) is set to Adm_Weight, then the distances in the linkdist file may be used to calculate the lengths of the demand paths during path placement. The only way to override this admin weight is to use the admin weight specified in the miscellaneous field of the bblink file for a particular link between two nodes. In the bblink file, use "DIST=x" (symmetric), "DISTA2Z=x", or "DISTZ2A=x" (asymmetric), where x is substituted by a number.

For a link between a node pair not listed in the linkdist file, the admin weight defaults to the linkdistunit parameter in the dparam file. This parameter can be specified in the "User-Defined Link Distance" function of the "Read Files" menu in the text version of BBDsgn. If linkdistunit is positive, that value is the default admin weight for all links. If linkdistunit is negative, the default admin weight for all links is calculated as the airline distance between each pair of nodes divided by the absolute value of linkdistunit and rounded up to the nearest integer. For example, if linkdistunit=-50, the user-defined distance for links from 1 to 50 miles is 1. Similarly, for links from 51 to 100 miles, the user-defined distance is set to 2.

NODEWEIGHT (nodeweight=filename)

  • Node weight, or Link Penalty for Design: A penalty at a node for purchasing links at it during a design. Use a number less than 100000. If 100000 or higher, this value has another meaning: no pass-through demands are allowed in design mode.

  • Trunk-bandwidth-limit: a maximum trunk bandwidth capacity at a node that gets used during design, and For example, if the trunk-bandwidth-limit is set to 5M (5Mbps) and the link type being designed for is a T1, then only 3 T1s (each ~1.5 Mbps) can be added since 4 T1s would exceed this limit.

  • Transit-bandwidth-limit: a maximum transit demand bandwidth capacity for a node that gets used for path placement. For example, specifying a limit of 0 will prevent pass-through demands at a node.


A node weight is required if maximum link bandwidth capacity is to be specified. The default Node Weight is 0 and the Default Maximum Link Bandwidth Capacity is infinity.

RSVBWFILE (rsvbwfile=filename)

The fixfat and fatpct parameters in the dparam file are used to globally define reserved bandwidth for all links in the network. To define reserved bandwidth for specific node pairs, the rsvbwfile should be used. Reserved bandwidth is calculated based on values in the rsvbwfile. For node pairs not defined in this file, reserved bandwidth is calculated based on the fixfat and fatpct global parameters. To follow the reservation constraints, BBDsgn will avoid using reserved bandwidth during path assignment and backbone design. In failure analysis/failure simulation routines, however, these reservation constraints are ignored.